This invention relates to an exercise treadmill, and more particularly, to an exercise treadmill having an improved slider bed.
Exercise treadmills are utilized in a variety of medical diagnostic and therapeutic treatments, particularly in cardiology. Also, exercise treadmills are utilized by exercise-conscious persons in that treadmills permit a person to more easily simulate a controlled walking, running, or jogging exercise program indoors with a minimum amount of space. The speed of exercise, the duration of the exercise period, and the work expended may be readily controlled by regulating the speed of the treadmill, the length of the exercise period, and by varying the inclination of the treadmill belt.
Typically, an exercise treadmill includes an endless belt entrained around a pair of spaced-apart rollers, with one of the rollers being driven at a predetermined speed such that the upper reach of the treadmill moves from a front to rear direction. In order for the user to remain stationary relative to a handlebar or the frame of the treadmill, the user must walk or run on the upper reach of the belt. By increasing or decreasing the surface speed of the belt, and by changing the inclination of the belt, the degree of physical energy expended by the user to keep pace with the belt may be selectively varied.
The upper reach of the belt must be supported. This may be accomplished by providing a plurality of closely-spaced rollers immediately below the upper reach of the belt. While these rollers provide little resistance to the movement of the belt and thus generate little or no friction on the belt, the rollers provide an uneven surface which may be felt by the user as he walks or runs on the belt. Another typical manner of supporting the belt is to provide a stationary slider plate or platen immediately below the upper reach of the belt. While this continuous slider plate or platen provides a continuous and, thus, a more comfortable surface for supporting the upper reach of the belt while the user runs or walks thereon, the use of a stationary slider plate generates considerably more friction with the moving belt, particularly in the areas where the user's foot momentarily contacts the belt. This friction results in the generation of heat, and may lead to excessive wear on the belt and/or the slider bed.
Numerous attempts have been made to overcome the problem of friction between the belt and the slider bed. The slider bed has been covered with a wax impregnated canvas, as shown in U.S. Pat. No. 3,659,845. Additionally, the slider belt has been made with a plurality of downwardly compressible air cells, and of a low friction (e.g., Teflon-coated nylon contact sheet, as shown in U.S. Pat. No. 3,689,066). Additionally, attempts have been made to provide for controlled leakage of air cells in order to provide an "air bearing" effect for journaling the upper reach of the belt on the bed. In Hesen, U.S. Pat. No. 3,703,284, a friction-reducing material (e.g., Teflon) has been utilized to cover the slider bed. It has also been suggested that the slider bed be made of a low-friction material, such as highly polished melamine (Formica) resin, as shown in U.S. Pat. No. 3,731,917.
Reference may also be made to such U.S. Pat. Nos. as 1,766,089, 1,824,406, 1,919,627, 2,969,768, 3,118,315, 3,332,683, 3,554,541, 3,606,320, 3,608,898, 3,643,943, 3,711,090, 3,711,812, 3,737,163, 3,826,491, 4,066,257, 4,227,487, 4,274,625, 4,334,676, 4,342,452, 4,344,616, and 4,350,336, in the same general field as the present invention.
However, in all of the prior art treadmills, the problems of belt and slider bed surface wear have not been overcome satisfactorily.